[PATCH v2 10/20] ceph_d_revalidate(): propagate stable name down into request enconding

Al Viro
2025-01-16T05:23:20Z

Currently get_fscrypt_altname() requires ->r_dentry->d_name to be stable
and it gets that in almost all cases. The only exception is ->d_revalidate(),
where we have a stable name, but it's passed separately - dentry->d_name
is not stable there.

Propagate it down to get_fscrypt_altname() as a new field of struct
ceph_mds_request - ->r_dname, to be used instead ->r_dentry->d_name
when non-NULL.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/ceph/dir.c | 2 ++
fs/ceph/mds_client.c | 9 ++++++---
fs/ceph/mds_client.h | 2 ++
3 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index dc5f55bebad7..62e99e65250d 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -1998,6 +1998,8 @@ static int ceph_d_revalidate(struct inode *dir, const struct qstr *name,
req->r_parent = dir;
ihold(dir);

+ req->r_dname = name;
+
mask = CEPH_STAT_CAP_INODE | CEPH_CAP_AUTH_SHARED;
if (ceph_security_xattr_wanted(dir))
mask |= CEPH_CAP_XATTR_SHARED;
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 219a2cc2bf3c..3b766b984713 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -2621,6 +2621,7 @@ static u8 *get_fscrypt_altname(const struct ceph_mds_request *req, u32 *plen)
{
struct inode *dir = req->r_parent;
struct dentry *dentry = req->r_dentry;
+ const struct qstr *name = req->r_dname;
u8 *cryptbuf = NULL;
u32 len = 0;
int ret = 0;
@@ -2641,8 +2642,10 @@ static u8 *get_fscrypt_altname(const struct ceph_mds_request *req, u32 *plen)
if (!fscrypt_has_encryption_key(dir))
goto success;

- if (!fscrypt_fname_encrypted_size(dir, dentry->d_name.len, NAME_MAX,
- &len)) {
+ if (!name)
+ name = &dentry->d_name;
+
+ if (!fscrypt_fname_encrypted_size(dir, name->len, NAME_MAX, &len)) {
WARN_ON_ONCE(1);
return ERR_PTR(-ENAMETOOLONG);
}
@@ -2657,7 +2660,7 @@ static u8 *get_fscrypt_altname(const struct ceph_mds_request *req, u32 *plen)
if (!cryptbuf)
return ERR_PTR(-ENOMEM);

- ret = fscrypt_fname_encrypt(dir, &dentry->d_name, cryptbuf, len);
+ ret = fscrypt_fname_encrypt(dir, name, cryptbuf, len);
if (ret) {
kfree(cryptbuf);
return ERR_PTR(ret);
diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
index 38bb7e0d2d79..7c9fee9e80d4 100644
--- a/fs/ceph/mds_client.h
+++ b/fs/ceph/mds_client.h
@@ -299,6 +299,8 @@ struct ceph_mds_request {
struct inode *r_target_inode; /* resulting inode */
struct inode *r_new_inode; /* new inode (for creates) */

+ const struct qstr *r_dname; /* stable name (for ->d_revalidate) */
+
#define CEPH_MDS_R_DIRECT_IS_HASH (1) /* r_direct_hash is valid */
#define CEPH_MDS_R_ABORTED (2) /* call was aborted */
#define CEPH_MDS_R_GOT_UNSAFE (3) /* got an unsafe reply */
--
2.39.5